Piston type pump



March 8, 1966 J, SADLER ET AL 3,238,890

PISTON TYPE PUMP Filed Oct. 1'7, 1963 3 Sheets-Sheet 5 FIG. '7

INVENTORS MAR/Pl I JJfiLER ERA/57 5. coo/r ROBERT AT iAfMuxE/v Arramve Vs United States Patent 3,238,890 PISTON TYPE PUMP Harry .I. Sadler, Minneapolis, Ernest E. Cook, Coon Rapids, and Robert F. Rasmussen, Minneapolis, Minn., assignors, by mesne assignments, to Hypro, Inc.,

Minneapolis, Minn., a corporation of Ohio Filed Oct. 17, 1963, Ser. No. 316,978

10 Claims. (Cl. 103-171) This invention relates to pumps and more particularly to a pump of the piston type with positive displacement. This application is a continuation-in-part of our application for Piston Type Pump, Serial No. 30,163, filed May 19, 1960, now abandoned.

It is the general object of the invention to provide a pump which not only is light in weight and economical in construction but also is high in capacity and efficient in operation.

More specifically, it is an object of the invention to provide a pump of the character described in which a dual piston is disposed diametrically across a hollow body having a closed loop with the piston drive exposed to atmosphere and not subjected to contact with the fluid being pumped The invention also has for an aim the provision of novel valve assemblies for controlling the flow of fluid within the pump which assemblies are unitized and which can be readily installed without requiring accurate machining of the pump housing.

A further object of the invention is to provide a pump which has simple cast body and cylinder heads which, when secured together, retain in rigid and sealed relation without internal fastening, all of the valve, cylinder and piston parts. Such arrangement, in addition to favoring economy, also greatly assists in the assemblage and repair of the pump units.

Another object of the invention is to provide a simple drive connection between an eccentric drive and two pistons which utilize but a single connecting rod without pin or pivot joints.

A further object of the invention is to provide a doubleacting piston pump in which cast passageways are smoothly and eificiently formed to produce a steady and full flow of fluid at a wide range of pressures.

A still further object is to provide a double-acting piston pump in which the body cylinders and working parts are symetrically disposed and contain identical and interchangeable parts to minimize cost of construction and replacement.

These and other objects and advantages of this inven tion more fully appear in the following description, made in connection with the accompanying drawings, wherein like reference characters refer to the same or similar parts throughout the several views and in which:

FIGURE 1 is a side elevation of the pump with the side cover partly broken away to show the piston drive assembly.

FIGURE 2 is an end view taken from the right in FIG- URE 1.

FIGURE 3 is an enlarged vertical section taken on the line 33 of FIGURE 2.

FIGURE 4 is an enlarged vertical section taken on the line 4-4 of FIGURE 1, certain parts being shown in full line representation.

FIGURE 5 is an exploded view of the poppet valve parts.

3,238,898 Patented Mar. 8, 1966 "ice FIGURE 6 is a sectional segment of the connecting rod and drive assembly taken on the line 66 of FIG- URE 4.

FIGURE 7 is a bottom plan view of a somewhat different housing head that may be utilized.

FIGURE 8 is a composite view of one of the improved valve assemblies, the bracketted individual views being a left end view, a side elevational view and a right end view, respectively.

FIGURE 9 is a sectional view taken in the direction of line 9-9 of FIGURE 8.

With continued reference to the drawings, the pump is shown in its entirety in FIGURES l and 2. The pump housing is designated generally as 10 and in turn constitutes a housing body 11, a housing head 12 and a housing foot 13. The housing 10 is in the form of a hollow closed loop shown in FIGURES 1 and 3, a continuous passageway 14 being formed throughout. Inwardly from housing 10 is a medial open space 15 as shown in FIG- URES 1 and 4 which space is open to the atmosphere.

The housing body 11 has a cylindrical bore 16 formed transversely of the closed loop housing and extending upwardly through the top 17 of housing body 11 and downwardly through bottom 18 thereof. In the form shown in the instant application, the cylinder bore has a single vertical axis which passes through the center of the medial open space 15 within the closed loop housing. Cylindrical bore 16 thus communicates between the endless passageway 14 and the atmospheric air in space 15.

That portion of the endless passageway which lies within the housing body 11 constitutes a pair of passageways 19 and 20 to the right and the left respectively of the medial open space 15 shown in FIGURE 3. Each of the upstanding passageways 19 and 20 terminates at top 17 and bottom 18 in an enlarged shouldered opening 21 as shown in FIGURE 3. The housing body 11 is also provided with a threaded inlet 22 and a threaded outlet 23 communicating respectively with the passageway portions 19 and 20 of the endless passageway 14.

Referring now to FIGURE 2, a large boss 24 is cast integrally with the body 11 and is provided with an opening 25 adapted to receive a roller bearing structure 26 as shown in FIGURE 4. A cap or cover 27 is removably secured to the housing body 11 to cover the atmospheric opening 15 when the pump is assembled.

Also constituting a part of the closed loop housing 10 is the housing head 12 which may be bolted thereon by means of cap screws 28 as shown in FIGURES 1 and 2. An endless groove 29 may be cast in face 30 and provided with a continuous sealing gasket 31 as shown in FIGURES 3 and 4. It will be observed that a portion 32 of the surface 30 extends marginally over the passageway openings 21 for a purpose to be subsequently disclosed. A contoured recess 33 is formed in the housing head 12 so as to complete the endless passageway 14 and provide communication between passageways 19, 20, and cylinder bore 16.

The housing foot 13 is similarly bolted to the housing body 11 by such means as cap screws 28 and the foot 13 is similar in construction to housing head 12 with the exception of the legs 34 which may be utilized to support the entire pump if desired. The housing foot 13 is provided with a marginally projecting surface 32, a contoured recess 33, groove 29, sealing gasket 31 and surface 30 for sealing against the opposed surface 18 of housing body 11, all as previously described in connection with the housing head 12.

At the upper and lower ends 17 and 18 respectively of housing body 11 and within the traversing cylinder bore 16 are positioned a pair of cylinder sleeves 35 as shown in FIGURES 3 and 4. The sleeves 35 have shouldered abutment at 36 with the bore 16 so that the outer terminal edge 37 lies flush with the plane of housing body top 17 and bottom 18 as shown. A groove 38 is formed annularly around each of the sleeves 35 and a seal such as O-ring 39 is positioned therein for making a pressuretight connection between the sleeve 35 and bore 16 of housing body 11. Sleeve 35 may be provided with skirt extensions 40 which project slightly into the atmospheric space as shown in FIGURE 3.

A piston assembly 41 has a connecting rod 42 and a piston 43 disposed at each end thereof as shown in FIG- URES 3 and 4. Where the cylinder sleeves 35 are di metrically opposed as in the instant disclosure, a single connecting rod 42 may be employed as shown in FIG- URE 4. Further, the rod 42 may be made of shaft material and formed with pins 44 at each end thereof. A piston backing plate 45 is positioned at each end of the connecting rod 42 upon the pins 44 and a piston cup 46 is in turn positioned upon the backing plate. A piston cup spreader 47 is then placed over the piston cup 46 and the spreader 47 is provided with a circumferential groove and O-ring cup spreader 48 as shown. A piston cap screw 49 extends axially through the piston assembly and is threadably received in the end of the connecting rod 42 so as to hold each of the piston assemblies in secured relation with respect to the rod.

Anotched area 50 which is substantially in the form of a longitudinal cylindrical segment is cut out of the connecting rod 42 as shown in FIGURES 4 and 6 so as to create a flattened surface 51 formed at the side of the connecting rod and a pair of longitudinally spaced bearing surfaces 52 extending laterally outward from the flattened surface 51. The notched out portion 50 of course leaves a substantial connecting portion 53 so that the connecting rod 42 will not be unduly weakened by the presence of the notch.

In order to drive the position assembly in reciprocation within the cylinder bore, a drive assembly 54 is provided. The drive constitutes a shaft 55 journaled in bearing 26 as shown in FIGURE 4 and the shaft may be provided with a coupling extension 56 as shown. Shaft 55 may be keyed with respect to bearing by such means as snap rings 57.

Eccentrically located with respect to the inner end 58 of shaft 55 is a crank pin 59 as shown in FIGURES 4 and 6. The crank pin 59 has a roller 60 rotatably mounted thereon and needle bearings 61 may be suitably interposed between pin 59 and roller 60 as shown in FIGURE 3. Roller 60 is adapted to interfit in the notch 50 with its outer circumference engaging the lateral bearing surfaces 52 as shown in FIGURE 4. The circumference of roller 60 may be convexed slightly in axial crosssection so that it will be self-aligning with respect to the bearing surfaces 52 on the connecting portion 53.

The flattened surface 51 lightly contacts or is closely positioned to the exposed end face 62 of roller 60 so that the flattened portion 51 will be keyed thereagainst and the connecting portion 53 prevented from rotating. The opposed bearing surfaces 52 will thus be kept in contact with the roller 60 at all times during operation of the pump.

Duplicate valve assemblies 63 are positioned in the open ends of each of the upstanding passageways 19 and formed in the housing body 11. The valve assemblies 63 are retained against shoulder 21 so that their outermost ends 64 will lie flush with the respective surfaces 17 and 18 at the top and bottom of housing body 11. The valve assemblies 63 are thus retained in position by the overhanging margins 32 of the housing head and foot portions 12 and 13. Similarly, the head and foot margins 32 bear against the outermost ends 37 of sleeves 35 and retain them in the ends of cylinder bore 16.

The valve assemblies 63 are shown in exploded view in FIGURE 5 and each constitutes a backup ring 65, a plastic seat 66, a poppet 67 provided with a spherical surface segment 68, a compression spring 69 and a spoked guide 70 as shown. The valves are reversible so that they can stop and permit flow of fluid in either direction through the passageways.

In the assembly of the pump, body housing 11 first is provided with the bearing 26 and drive assembly 54, the eccentric crank pin and roller bearing being secured to the inner end of the shaft 55 as shown in FIGURES 4 and 5. The piston assembly 41 is then placed in position with the pistons 43 lying in the cylindrical bore 16 and the notchedout portion 50 of connecting portion 53 interfitting over the roller 60 as shown in FIGURES 3, 4 and 6. The cylinder sleeves 35 with their sealing rings 39 attached thereto are then inserted into the cylinder bore 16 at each end, the sleeves serving to abut and hold the bearing as sembly 26 in place within the boss 24. Poppet valve assemblies 63 are then inserted into the opened shouldered ends of passageways 19 and 20, the poppet valves in passage 19 permitting flow outwardly thereof by checking the return flow therethrough. The valve assemblies 63 which are inserted into the ends of passageway 20 are inverted so as to permit flow of fluid into the ends thereof but to check the flow reversely outward. The housing head 12 and foot 13 are then provided with sealing rings 31 and fastened securely by means of cap screws 28 to the housing body 11 so as to abut and retain the valve assemblies and cylinder sleeves in firmly seated relation. It will be observed that cap screws 28, once removed, will permit disassembly of the pump.

Although the valve assemblies 63 have functioned well in practice, they are somewhat difiicult to install due to the rather large number of parts plus the fact that they cannot be pre-assembled. Another disadvantage stems from the fact that the housing body 11 must be fairly accurately machined in order to accommodate properly these assemblies 63.

Accordingly, an improved valve assembly has been de= picted in FIGURES 8 and 9, such assembly having been denoted generally by the reference numeral 163. The unitized assembly comprises a metallic seat member 166 formed with a tapered seating surface 166a as seen in FIGURE 9. A cup-shaped poppet 167 of sheet metal has a tapered or reversely flared flange 168 which seats against the surface 166a when the valve is closed, the taper of the flange complementing that of the surface 166a which taper is easily provided by a simple metal forming or stamping operation. A compression spring 169 has one end received in the annular groove that is formed between the cylindrical wall of the poppet 167 and its flange 168. A spoked retaining sleeve or guide 170 has a centrally disposed bushing 171 provided with a shoulder at 172 for abutting the other end of the spring 169. In this way the spring 169 acts against the poppet 167 in a direction to normally urge its flange 168 against the seating surface 166a. The guide 170 may be fabricated from a suitable plastic, such as nylon, and through the agency of an integral rib at 173 the guide 170 can be fixedly mated with the metallic seat member 166, the member 166 having an annular groove 174 for the reception of said rib.

The seat member 166 is formed with a peripheral groove at 175 for the accommodation of a resilient O- ring 176. As can be seen from FIGURE 3, the cylindrical portion of the various shouldered openings 21 must be rather precisely machined in order to provide a relatively tight fit with the circumstance of the various parts 65, 66 and 70 comprising the valve assemblies 63. No precision machining is needed when utilizing the modified valve assemblies 163, for the O-ring will compress only to the extent required to provide the needed sealing action around each valve assembly, assuming that the outer diameter of the unitized assembly 163 is somewhat less than the diameter of the shouldered opening 21.

At this time attention is directed to FIGURE 7 where a modified housing head 112 is pictured. As with the head 12, there is an endless groove 129 formed in its face 130 with which the sealing gasket 31 of FIGURES 3 and 4 is placed. A portion 132 at each end of the face 130 extends marginally over the passageway openings 21 when the head 112 is attached to the housing body 11. As can be perceived from FIGURE 7, this marginal portion 132 subtends an angle greater than 180 degrees so as to overlie a substantial portion of the modified valve assembly 163 when installed, thereby assuring a firm retention of each assembly 163 during operation of the pump. A contoured recess 133 in the face 130 corresponds generally to the recess 33 in the face 30 of the head 12. Four apertures 134 are provided in the head 112 for the bolts 28.

In the operation of the pump, fluid enters the inlet 22 and when shaft 55 is rotated the piston assembly 41 will be reciprocated to cause alternate flow of fluid into the respective cylinder sleeves 35 and ejection thereof when the piston assembly reverses its direction, the fluid being discharged from outlet 23 for each half revolution of the shaft 55.

Since the roller 60 has a slightly convex bearing surface, it is not essential that the cast housing body 11 be machined to a high degree of accuracy. Slight misalignment will be automatically compensated for by the character of the roller bearing surface. Since the crank .pin and roller as well as the shaft 55 and bearing assembly 26 are not located within, or subjected to, direct contact with the endless passageway 14, no material pumped into the unit will come in contact with these members nor is there any opportunity for fluid to leak from the pump into the drive parts.

It will, of course, be understood that various changes may be made in the form, details, arrangements and proportions of the parts without departing from the scope of the invention as set forth in the appended claims.

What is claimed is:

1. A piston type pump comprising, a housing body having horizontal flat top and bottom, an upstanding cylindnical bore extending through the flat top and bottom thereof and having an atmospheric opening medially of the body constituting a lateral drive-receiving enlargement at an intermediate portion of said cylindrical bore, a pair of passageways each extending through the flat top and bottom of said housing body at opposed sides of said cylindrical bore, an inlet communicating with one of said passageways, an outlet communicating with the other of said passageways, a valve assembly inserted in each end of each passageway, a cylindrical sleeve inserted in each end of said cylindrical bore, a piston in each of said cylindrical bores, a drive assembly reciprocably connected to the pistons, a housing head secured over the cylinder bore and the end of each passageway at the top of said housing body, a housing foot secured over the cylinder bore and the end of each passageway at the bottom of said body, each of said head and foot having a flat forward area along and adjacent portions of the periphery thereof and a rearw-ardly recessed area inscribed within said flat forward area and providing communication between said pair of passageways and said cylinder bore, each of said housing head and foot further having a portion of said fiat area thereof abutting associated cylinder sleeves and valve assemblies at marginal portions thereof whereby to hold the sleeves and valve assemblies in their inserted position without additional fastening means.

2. The structure set forth in claim 1 wherein each of said valve assemblies includes a resilient rin-g extending about its periphery for effecting a seal with its particular passageway.

3. The structure set forth in claim 1 in which said valve assemblies are each constructed of two outer parts interfitted to provide a unit, one of said parts having a valve seat, and said unit further including a spring pressed poppet engageable with said seat.

4. The structure of claim 3 including a compressible ring extending peripherally about one of said parts to provide a seal with its respective passageways, said parts being of smaller cross-sections than the passageway in which they are placed.

5. A piston type pump comprising, a housing defining a closed loop and having an endless passageway formed therein, said closed loop surrounding an inner open space, an inlet communicating with said endless passageway, an outlet spaced from said inlet and also communicating with said endless passageway, a pair of open ended cylinders lying mutually in spaced relation between said inlet and said outlet, each communicating with the endless passageway and with said inner open space, a piston reciprocably positioned in each of said cylinders, valve means in said passageway interposed between said inlet and each of said cylinders, valve means in said passageway interposed between said outlet and each of said cylinders, each of said valve means including a member providing a tapered seat and a poppet having a correspondingly tapered flange enga-geable with said seat, and drive means operably connected to said pistons through said inner open space for reciprocating the same.

6. The structure set forth in claim 5 wherein said poppet is of sheet material, said flange flaring outward and rear-ward to provide an annular groove, and a coil spring having one end received in said groove for biasing said poppet in a direction to cause engagement of said flange with said seat.

7. The piston type pump as defined in claim 1 being particularly characterized in that said flat area abutting associated cylinder sleeves and valve assemblies lies along the lateral edges only of the area of communication be tween said pair of passageways and said cylinder bore.

8. A piston type pump comprising, a housing defining a closed loop and having an endless passageway formed therein, said closed loop surrounding an inner open space, an inlet communicating with said endless passageway, an outlet spaced from said inlet and also communicating with said endless passageway, a pair of open ended cylinders lying mutually in spaced relation between said inlet and said outlet, each communicating with the endless passageway and with said inner open space, a piston reciprocably positioned in each of said cylinders, valve means in said passageway interposed between said inlet and each of said cylinders, valve means in said passageway interposed between said outlet and each of said cylinders, each of said valve means being a self-contained unit having a resilient ring extending about its outer periphery for effecting a seal with the inner cylindrical wall of its particular passageway, each unit being comprised of two cylindrical parts of lesser diameter than that of the particular passageway in which it is placed, one of said pairs having an annular groove in which said resilient ring is disposed, said resilient ring projecting radially beyond said groove so as to bear tightly against said passageway wall, and drive means operably connected to said pistons through said inner open space for reciprocating the same.

9. A piston type pump comprising, a housing defining a closed loop and having an endless passageway formed therein, said closed loop surrounding an inner open space, an inlet communicating with said endless passageway, an outlet spaced from said inlet and also communicating with said endless passageway, a pair of open ended cylinders lying mutually in spaced relation between said inlet and said outlet, each communicating with the endless passageway and with said inner open space, said cylinders being diametrically opposed, a piston reciprocably positioned in each of said cylinders, a single connecting rod rigidly secured at its respective ends to said pistons, said connecting rod having a notch cut in the side thereof intermediate its ends and lying within said inner open space, said notch forming a first flat surface parallel to the axis of said rod and a pair of second flat confronting abutment surfaces formed at right angles to said first flat surface, valve means in said passageway interposed between said inlet in each of said cylinders, valve means in said passageway interposed between said outlet in each of said cylinders, a drive shaft journaled normally to said connecting rod and having an eccentric crank pin projecting into said notch, and a roller journaled in said crank pin, said roller circumferentially bearing substantially against both of said confronting abutment surfaces and also bearing endwise against said first flat surface, said roller having an outer circumferential bearing surface which is slightly convexed in axial crosssection.

10. The structure set forth in claim 8 wherein said parts are retained together by overlapping port-ions, one of said overlapping portions having an annular rib thereon and other of said overlapping portions having a groove in which said rib is received.

References Cited by the Examiner UNITED STATES PATENTS 232,520 9/1880 Lighthall 103171 1,671,701 5/1928 Coats 30872 1,705,772 3/1929 Kimmel 230-172 1,804,909 5/ 1931 Wistrand 308209 2,146,709 2/1939 Bird et a1. 103153 2,363,119 11/ 1944 Cros'sman 103171 2,771,037 11/1956 Johnston 103171 X FOREIGN PATENTS 1,033,552 4/1953 France.

MARK NEWMAN, Primary Examiner.

WARREN E. COLEMAN, DONLEY I. STOCKING, Examiners. 

1. A PISTON TYPE PUMP COMPRISING, A HOUSING BODY HAVING HORIZONTAL FLAT TOP AND BOTTOM, AN UPSTANDING CYLINDRICAL BORE EXTENDING THROUGH THE FLAT TOP AND BOTTOM THEREOF AND HAVING AN ATMOSPHERIC OPENING MEDIALLY OF THE BODY CONSTITUTING A LATERAL DRIVE-RECEIVING ENLARGEMENT AT AN INTERMEDIATE PORTION OF SAID CYLINDRICAL BORE, A PAIR OF PASSAGEWAYS EACH EXTENDING THROUGH THE FLAT TOP AND BOTTOM OF SAID HOUSING BODY AT OPPOSED SIDES OF SAID CYLINDRICAL BORE, AN INLET COMMUNICATING WITH ONE OF SAID PASSAGEWAYS, AN OUTLET COMMUNICATING WITH THE OTHER OF SAID PASSAGEWAYS, A VALVE ASSEMBLY INSERTED IN EACH END OF EACH PASSAGEWAY, A CYLINDRICAL SLEEVE INSERTED IN EACH END OF SAID CYLINDRICAL BORE, A PISTON IN EACH OF SAID CYLINDRICAL BORES, A DRIVE ASSEMBLY RECIPROCABLY CONNECTED TO THE PISTONS, A HOUSING HEAD SECURED OVER THE CYLINDER BORE AND THE END OF EACH PASSAGEWAY AT THE TOP OF SAID HOUSING BODY, A HOUSING FOOT SECURED OVER THE CYLINDER BORE AND THE END OF EACH PASSAGEWAY AT THE BOTTOM OF SAID BODY, EACH OF SAID HEAD AND FOOT HAVING A FLAT FORWARD AREA ALONG AND ADJACENT PORTIONS OF THE PERIPHERY THEREOF AND A REARWARDLY RECESSED AREA INSCRIBED WITHIN SAID FLAT FORWARD AREA AND PROVIDING COMMUNICATION BETWEEN SAID PAIR OF PASSAGEWAYS AND SAID CYLINDER BORE, EACH OF SAID HOUSING HEAD AND FOOT FURTHER HAVING A PORTION OF SAID FLAT AREA THEREOF ABUTTING ASSOCIATED CYLINDER SLEEVES AND VALVE ASSEMBLIES AT MARGINAL PORTIONS THEREOF WHEREBY TO HOLD THE SLEEVES AND VALVE ASSEMBLIES IN THEIR INSERTED POSITION WITHOUT ADDITIONAL FASTENING MEANS. 